The present invention relates to a rotor for an electrical machine.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
Rotors or armatures can be used for servomotors, for example, and in particular for motors having high rotational speeds. Armatures featuring external magnets are normally bandaged using tape made of tear-resistant materials. Locking plates are normally used to hold the start and the end of the bandage in the case of laminated armatures. On most armatures, the start and the end of the bandage start and end at locking plates due to the small air gap. These locking plates fit closely against the plane surfaces of the armature end faces. Due to length tolerances in the laminated core and length tolerances of the magnets, gaps remain between the magnets and between magnet and locking plate.
The magnets are conventionally distributed axially along the length of the armature between the locking plates. For process engineering reasons, it has not been possible to avoid axial gaps until now. During unilateral location of the magnets, the magnets were conventionally placed on one of the locking plates unilaterally, and the resulting gap between the magnets and the insulating plate was partially filled by an additional element (similar to an O-ring). Owing to the circumferential gaps that are inevitably formed due to the nature of the process, the bandage applied under pretension is partially pulled between the magnets and/or between magnet and locking plate in a circumferential direction. As a consequence of the bandage tape being partially pulled into the gap, the possible tension when bandaging the armature is limited, and magnets are displaced from their ideal position in some cases.
It would therefore be desirable and advantageous to provide an improved rotor for an electrical machine to obviate prior art shortcomings and to allow operation at a particularly high rotational speed.